Injuries to the peripheral nervous system result in partial or total paralysis of the affected tissues if untreated, resulting in a significant quality of life deficit. Nerve injuries are a result of trauma, disease, and certain surgical procedures. For example, oncological surgery to remove tumors in the cranial base requires transection, and often resection, of the facial nerve. Current clinical treatments have led to incomplete and unsatisfactory recovery of motor and sensory function. Previous studies have shown the efficacy of a collagen-glycosaminoglycan (CG) matrix, ensheathed by a collagen nerve guide, to facilitate and enhance axonal regrowth. The long-term goal of the proposed study is to develop a resorbable collagen device that results in regeneration that meets or exceeds the current clinical standards. The proposed program is the result of the multiyear experience of the experimental team in synthesizing CG matrices and testing the response of injured tissues to these matrices. The primary focus of the research is on determination of the long-term recovery of peripheral nerves repaired with a family of collagen implants. Each objective varies one property of the implants: the presence or absence of a CG matrix filling a collagen tube, the length of gap injury the CG matrix is bridging, and the degradation rate of the collagen tube. Differences in the return of electrophysiological function and axonal structure will be evaluated between nerves regenerated through different collagen implants. The proposed study will provide quantitative information, not currently available, regarding the extent of steady state recovery compared to normal nerve, the effect of gap length on recovery of structure and function, and the optimum degradation rate of resorbable collagen tubes. It will also provide information on the kinetics of electrophysiological recovery of the regenerating nerve when treated with various implants and gap lengths. These data will be useful for all investigators studying the efficacy of devices for peripheral nerve regeneration.